Absorbent article

ABSTRACT

An absorbent article, especially an incontinence pad, having a length and a width extension, the length being greater than the width, and including absorbent core material, wherein the absorbent core material forms a central portion ( 6 ) and a pair of longitudinally extending side portions ( 7 ), the flexural rigidity of the article ( 1 ) at the side portions ( 7 ) is between 3 and 20% of the flexural rigidity of the article ( 1 ) of the central portion ( 6 ) at a location opposite the side portions ( 7 ), preferably between 4 and 15%, most preferred between 4 and 10%.

FIELD OF INVENTION

The present disclosure relates to an absorbent article, having a lengthand a width extension, said length being greater than said width andcomprising absorbent core material. The absorbent article can be asanitary napkin, a panty liner, an incontinence pad or the like. Theinvention is especially useful for an incontinence pad.

TECHNICAL BACKGROUND

Absorbent articles of the above mentioned kind are intended to absorbbody liquids such as urine and blood. To this end, the articles are wornclose to the wearer's body and usually placed in the wearer's underwear.For the comfort of the wearer and for the most efficient use of thearticle, it is thus of importance that the article may adjust well tothe wearer's body.

Flexible articles generally have the advantage of adapting to the user'sbody, since they will be easily compressible. However, flexible articlesmay have the disadvantage that after compression e.g. between the thighsof the user, they cannot sufficiently fill the space there between,which might result in unwanted leakage at the longitudinal edges of thearticle. Relatively flexible products further have a tendency that thecompression will result in the article having a series of folding linesor creases.

Stiffer articles might maintain their structural integrity better thanmore flexible products, but may have the disadvantage of being perceivedas more uncomfortable. Also, stiffer articles may, once they do becomecompressed, be compressed substantially along one line only, giving riseto a V-shaped article which may be subject to leakage problems similarlyto more flexible products. In use, this type of product will normallyfold such that, in use, the shape corresponds to an inverted V betweenthe thighs of the user.

A known article in the form of an incontinence pad is formed in anelongate shape having parallel longitudinal edges. The longitudinaledges at the centre portion of the product are provided with an elasticmaterial which functions so as to pull the longitudinal ends of thearticle towards each other, resulting in a longitudinally cup-shapedarticle thus intended to conform to the body of the wearer. Further, thelongitudinal edges having the elastic material will extend upwardly soas to form an arc-shaped article also in a transverse direction thereof,at least at the centre portion of the article. This feature may act soas to diminish the risk of leakage of body fluids.

Although well functioning for many users, some users of theabove-mentioned article report that the regions of elastic material,when absorbing body liquid, might feel humid. Further, there might be arisk of leakage at the sides of the product.

JP2002238948 describes an absorbent article such as a sanitary napkin,an incontinence pad, a panty liner or the like. The article comprises anabsorbent having an upper absorber and a smaller sized lower absorberlaminated to the back side of the upper absorber. Grooves are formed onthe part corresponding to the lower absorber on the upper absorber.Hence, the upper absorber may be projected upwardly at the part thereofbeing positioned on the lower absorber. Hence, the product may form adownwardly directed arc-shape in a transverse direction thereof.

Thus, there is a need for an absorbent article, in particular anincontinence pad, which may adapt to the wearer's body and which limitsthe problems of humidity and/or leakage.

OBJECT AND SUMMARY

One object is to provide an absorbent article which adapts well to thewearer's body and diminishes any leakage problems. Further, the articleshould preferably be suitable as an incontinence pad.

The above-mentioned object is achieved by an absorbent article,especially an incontinence guard having a length and a width extension,said length being greater than said width, and comprising absorbent corematerial, wherein

the flexural rigidity of the side portions is between 3 and 20% of theflexural rigidity of the article (1) of the central portion (6) at alocation opposite the side portions (7), preferably between 4 and 15%,most preferred between 4 and 10%.

The flexural rigidities are measured according to the method as will bedescribed later on in the application.

It has been found, that the above relationship between the rigidity ofthe side portions and the central portion of the article results in anarticle where the side portions will deform prior to the centralportion, such that the side portions enable the required adaptation tothe body of the user, whereas the central portion maintains sufficientstructural integrity to diminish any leakage problems.

Advantageously, the flexural rigidity of the article at the sideportions may be between 0.35 and 1.1. Advantageously, the flexuralrigidity of the article at the central portion at a location oppositethe side portions is between 6.5 and 10.1. The measurements are made inaccordance with the method as described herein.

Advantageously, the thickness of the article at of the side portions isless than the thickness of the central portion at a location oppositethe side portions. Thus, the side portions will be more easily foldablethan the central portion, such that the desired form of the article whenin use is achieved.

In this case, it has been found to be suitable that the thickness ofarticle at the side portions may be between 40 and 80% of the thicknessof the article at the central portion at a location opposite the sideportions, preferably between 50 and 70%, most preferred between 55 and65%.

Preferably, the absorbent article may comprise a pair of folding linesbeing provided so as to divide said absorbent core material into saidcentral portion and said pair of longitudinal side portions. The foldinglines have the advantage that the site of folding of the article when inuse may be controlled, which contributes to the desired deformation ofthe product.

The folding lines are generally lines being provided so as to facilitatethe folding of the side portions. Advantageously, the folding lines maybe formed by compression of the absorbent material.

The folding lines may completely separate the absorbent material in theside portions from the absorbent material in the central portion.

Alternatively, the folding lines may only partly separate the absorbentmaterial in the side portions from the absorbent material in the centralportion.

Preferably, the folding lines are positioned and extending along alength such that, when the article is in use, the folding lines aregenerally positioned so as to extend along the crotch area of the user,starting from the gracilis tendons and ending in the region of theperineum, whereby the side portions may extend from the central portiontowards the user so as to form an arc shape as seen in a transversaldirection of the article.

Hence, the start and end positions of the folding lines are suitable forplacement at the gracilis tendons of a user and in the region of theperineum of a user, respectively. Further, the folding lines enables theside portions of the article to fold so as to adapt to the body of theuser along the crotch area between the gracilis tendons and the regionof the perineum, without unnecessarily effecting the width extension ofthe product at the central portion, which may extend in front and behindthe pair of side portions. Thus, adaptation to the wearer's body isgenerally provided in the centre region of the article, where this ismost wanted. At the same time, the front and back region of the articleis not adversely affected by the adaptation of the middle region.

Advantageously, the folding lines may be extending concavely along thearticle, so as to provide a shape being suitable for fitting to the bodyof a user.

Preferably, the folding lines have a length of about 60 to 170 mm,preferably 80 to 140 mm, most preferred 90 to 130 mm.

The folding lines may advantageously extend along about ⅓ of the totallength of the article.

The folding lines are generally lines being provided so as to facilitatethe folding of the side portions. Advantageously, the folding lines maybe formed by compression of the absorbent material. The compressionlines may extend e.g. wholly or partly through the absorbent core only,through the absorbent core and the topsheet material, or through theabsorbent core, a topsheet material and a backsheet material.

The folding lines may completely separate the absorbent material in theside portions from the absorbent material in the central portion.

Alternatively, the folding lines may only partly separate the absorbentmaterial in the side portions from the absorbent material in the centralportion.

In a preferred embodiment, the outer longitudinal edges of saidabsorbent material forms three convex lobes,

-   -   said pair of folding lines extend concavely between the        longitudinal ends of the middle one of said three lobes,    -   so as to divide the absorbent core material into a central        portion and a pair of longitudinal side portions,    -   such that, when the article is in use, the folding lines are        generally positioned so as to along the crotch area of the user,        starting from the gracilis tendons and ending in the region of        the perineum, whereby the side portions may extend from the        central portion towards the user so as to form an arc shape as        seen in a transversal direction of the article.

The three-lobe shape of the article is well adjusted to the body of awearer in that the two indentations (of concave shape) being formedbetween the first and middle lobes, and the middle and third lobe, aresuitable for placement at the gracilis tendons of a user and in theregion of the perineum of a user, respectively. Further, the concavefolding lines enable the side portions of the article to fold so as toadapt to the body of the user along the crotch area between the gracilistendons and the region of the perineum, without unnecessarily affectingthe width extension of the product at the first and third lobes, beingpositioned in front and at the back of said crotch area. Thus,adaptation to the wearer's body is generally provided in the centreregion of the article, where this is most wanted. At the same time, thefront and back region of the article is not adversely affected by theadaptation of the middle region.

The folding lines are such that side portions may extend from thecentral portion towards the user so as to form an arc shape as seen in atransversal direction of the article. This configuration of the articleis believed to be the most advantageous in order to diminish leakagefrom the product. However, it is not excluded that the side portions mayalternatively extend from the central portion away from the user. Inthis configuration, the adaptation to the user's body is achieved, whichalso contributes to diminishing the leakage problems.

The three-lobe shape of the article has the additional advantage that itmay be adapted so as to provide efficient use of the starting materialsfor manufacture of the article. Such starting materials are generallyweb-shaped with a constant width. With a three-lobe shape, the materialwaste during manufacture may be kept relatively low which contributes tothe cost-effectiveness and environmental-friendliness of the article.

To achieve a good fit with the tendons of the wearer, the length betweenthe longitudinal ends of the middle lobe may be about 60 to 170 mm,preferably 80 to 140 mm, most preferred 90 to 130 mm.

Advantageously, the middle lobe may extend along about ⅓ of the totallength of the article. Preferably, the front and back lobe will thenalso extend along about ⅓ of the total length, such that each lobeextends along about ⅓ of the total length of the article.

The maximum width of the middle lobe may be between 60 and 150 mm,preferably between 70 and 130 mm, most preferred between 80 and 120 mm.Further, the maximum width of the middle lobe divided by the width ofthe absorbent core at one of the ends of said middle lobe mayadvantageously be between 110 and 180%, preferably 110 and 150%, mostpreferred 110 and 130%. Advantageously, the distance between the maximumwidth of the middle lobe and the adjacent folding line is less than 30mm, preferably in the range 10 to 30 mm, most preferred in the range 15to 25 mm.

The measures and proportions as mentioned above have been found toprovide particularly good adjustment to the body of a wearer.

Preferably the minimum width of the article is the width as measured ateither of the ends of the middle lobe. Hence, the minimum width of thearticle is the width where the folding lines start and/or begin. Thisconfiguration is advantageous in order to provide the required room forthe user's body e.g. at the gracilis tendons and the region of theperineum. In this context, the minimum width refers to the width alongthe essential length of the article. It is possible that the width ofthe product become somewhat narrower at the end of the product, wherethe article width might successively diminish.

The widths at the ends of the middle lobe may advantageously be in therange 30 to 100 mm, preferably 40 to 90 mm, most preferred 60 to 85 mm.Suitably, the widths at the two ends of the middle lobe may beessentially the same.

Advantageously, the maximum widths of the three lobes are substantiallythe same. This particular configuration provides good adjustment to thewearer's body. Further, it is advantageous from a manufacturing point ofview. Since the starting materials for manufacturing the article aregenerally band-shaped, the width of the bands may be selected to conformto the maximum width of the product being the width of the three lobes.Hence, very small amounts of material will be wasted during manufactureof the product.

Absorbent articles are often provided with an adhesive at a garmentfacing side thereof, so as to enable attachment to the underwear of auser. Advantageously, a garment facing side of the article may be freefrom adhesive at the side portions. Thus, the folding of the sideportions is not restricted by the shape or elasticity of theundergarment.

Preferably, the absorbent core material may comprise an upper absorbentcore and a lower absorbent core. “Upper” as used herein relates to thedirection of the product intended to be positioned closer to the wearerwhen in use, whereas “lower” as used herein relates to the direction ofthe product closer to the garment-facing side thereof.

Preferably, the absorbent core material may comprise an upper absorbentcore and a lower absorbent core. “Upper” as used herein relates to thedirection of the product intended to be positioned closer to the wearerwhen in use, whereas “lower” as used herein relates to the direction ofthe product closer to the garment-facing side thereof.

Advantageously, one of the upper and lower absorbent core may be widerthan the other as measured at the middle lobe of the article. In thisconfiguration, the side portions will comprise at least an areaincluding absorbent material from the widest of the cores only. This isbelieved to be beneficial for folding of the side portions of thearticle when in use.

In one embodiment, the lower absorbent core may be wider than the upperabsorbent core as measured at the middle lobe of the article. In thisconfiguration, side portions will comprise at least an area includingabsorbent material from the lower absorbent core only. This is believedto be beneficial for upward folding of the side portions of the articlewhen in use.

Preferably, one of the upper and lower absorbent core may be wider thanthe other as measured at the middle lobe of the article, and the foldinglines may extend along the least wide of the cores, such that the sideportions essentially comprise absorbent material from the widest of thecores only. Hence, controlled folding of the side portions isfacilitated.

If the lower absorbent core is wider than the upper absorbent core asmeasured at the middle lobe of the article, the folding lines maypreferably extend along the longitudinal sides of the upper absorbentcore, such that said side portions essentially comprise absorbentmaterial from the second absorbent core only.

It may be understood, that it is generally desired that the sideportions may be folded along the folding lines, whereas the centralportion of the article in between the folding lines may be keptrelatively smooth. This contributes to the above-mentioned effect thatthe central portion structure is kept relatively unaffected by theadjustment to the body, which is performed by the side portions. Hence,the stability and stable positioning of the article may be ensured.

Advantageously, one of the upper and lower absorbent cores may be longerthan the lower absorbent core as measured in the longitudinal directionof the article. In this configuration a maximum amount of absorbent corematerial is provided near to the centre of the product. Further, thelongitudinal end portions of the product are relatively thin, whichcontributes to the comfort and aesthetics of the product when in use.

Preferably, one of the absorbent cores may be generally hour-glassshaped (also called “dog-bone-shaped”). This shape is particularlysuitable also for the centre portion of the absorbent material, as it iswell suited to fit between the wearer's legs. Hence, the first convexlobe, the concave folding lines and the third convex lobe may togetherform an hour-glass shape.

Advantageously, the other one of the absorbent cores is generallycircular or oval. This shape enables the convex middle lobe of theproduct to be formed by the circular or oval edges of the lowerabsorbent core.

When using an upper and a lower absorbent core, the thickness of saidside portions may include the thickness of the widest one of the upperand lower absorbent core, and the thickness of the central portion at alocation opposite the side portions may include the thickness of thelower absorbent core plus the thickness of the upper absorbent core.

The method used for measuring flexural rigidity will be described in thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described in thefollowing in greater detail by way of example and with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic view from above of an absorbent article accordingto one embodiment of the invention.

FIG. 2 is a section along the line II-II in FIG. 1, depicting only theabsorbent core portion of the article.

FIG. 3 is a schematic view from above of an absorbent article accordingto a second embodiment of the invention.

FIG. 4 is a section along the line IV-IV in FIG. 3, depicting only theabsorbent core portion of the article.

FIG. 5 is a view from above of the article in FIG. 1, but comprisingfurther details regarding the topsheet etc.

FIG. 6 is a section according to the line VI-VI in FIG. 5.

FIGS. 7 and 8 illustrate schematically the testing equipment used forthe flexural rigidity test as described herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following examples or provided for illustrative purposes only andare not intended to limit the scope of the invention in any way.

The term “absorbent article” refers to products that are placed againstthe skin of the wearer to absorb and contain body exudates, like urine,and menstrual fluid. The disclosure mainly refers to disposableabsorbent articles, which means articles that are not intended to belaundered or otherwise restored or reused as an absorbent article afteruse.

FIG. 1 illustrates an absorbent article in the form of an incontinencepad 1. In its most common form the absorbent article comprises anabsorbent core and a cover enclosing the absorbent core. The covercomprises a liquid pervious topsheet on the wearer facing side of theabsorbent core and a liquid barrier backsheet material on the garmentfacing side of the absorbent core.

Details regarding the general construction of various layer sheets willbe described in more detail later on in relation to FIG. 4.

The article 1 of FIG. 1 has a length and a width extension, wherein thetotal length (L) is greater than the maximum width (d). The article 1comprises, as is conventional in the art, absorbent core material.

As illustrated in FIG. 1, the outer longitudinal edges of the absorbentmaterial form three convex lobes 2, 3, 4; a first lobe 2, a middle lobe3, and a third lobe 4. A pair of folding lines 5 extend concavelybetween the longitudinal ends of the middle one 3 of said three lobes 2,3, 4, so as to divide the absorbent core material into a central portion6 and a pair of longitudinal side portions 7.

When the article 1 is in use, the folding lines 5 are generallypositioned so as to extend along the crotch area of the user, startingfrom the gracilis tendons and ending in the region of the perineum,whereby the side portions 7 may extend from the central portion 6towards the user so as to form an arc shape as seen in a transversaldirection of the article 1.

In the illustrated embodiment, the lengths a, b, c of the three lobes 2,3, 4 are generally equal and approximately ⅓ of the total length L ofthe product. With this configuration, the product is symmetrical and socan be used with either of the first 2 and the third lobe 4 as the frontend.

Regarding the length b between the longitudinal ends of the middle lobe3, this is in the illustrated embodiment about 11 cm, whereas the totallength of the product is about 33 cm. As explained above, these lengthsmay vary within suitable intervals. The total length of the product mayfor example vary between 15 and 45 cm.

It is understood that with the ends of the lobes is meant the ends ofthe respective convex portion of the longitudinal edges of the absorbentmaterial. Hence, the length b of the middle lobe is measured from themidst of the concave portions formed in-between the three convex lobes.Since the concave portions between the lobes will function toaccommodate the user's body, e.g. the gracilis tendons of the user andthe perineum region, the distance between the concave portions, andhence the length of the middle lobe, should preferably be adapted tothis anatomical distance.

In the illustrated embodiment, the maximum width (d) of the middle lobe(3) is about 10 cm. Further, in this case, the maximum widths (d) of allthree lobes are the same. The width (e) of the article as measured atone of the ends of the middle lobe, in this case being the minimum widthof the product, is about 8 cm.

(From the exemplified dimensions, it is understood that the sideportions 7 of the absorbent core material are different from structurescommonly referred to as “wings” or “flaps” and provided in prior artproducts in order to ensure fastening to the undergarment. Wings orflaps are generally dimensioned to be folded around and fastened to thewearer's undergarment.)

As illustrated in FIG. 1, two folding lines 5 are formed extendingconcavely along the article between the ends of the middle lobe 3. Thefolding lines are intended to facilitate the folding of the sideportions 7 of the core in relation to the central portion 6.

In the illustrated embodiment, the folding lines 5 are formed bycompression of the absorbent material. In this case, the compressionlines 5 extend to a depth in the absorbent material so as to provide anindentation or groove forming the compression line, but not so deep asto completely separate the absorbent material in side portions 7 fromthe absorbent material in the central portion 6 (See FIG. 2). Hence, thecompression lines in this case only partly separate the absorbentmaterial in the side portions 7 from the absorbent material in thecentral portion 6. In this embodiment, body fluid absorbed by theabsorbent material may thus travel in the absorbent material from theside portions 7 towards the central portion 6 or vice versa.

However, other embodiments are possible in which the compression linesmay extend all the way through the absorbent material so as tocompletely separate the absorbent material in the side portions 7 fromthe central portion 6.

Further, regardless of whether the compression lines extend to a depthbeing equal to the depth of the absorbent material or not, thecompression lines may be continuous, as in the illustrated embodiment,or discontinuous (a broken or dashed line).

Selection between the different alternatives of compression lines may bemade taking the fluid distribution in the absorbent material as well asthe required tendency of the side portions to fold into consideration.

The fluid distribution in the product may be delayed by the use ofcompression lines as a temporary barrier against flow.

The compression lines may be made in the absorbent core only, orextending into other components of the product such as a top sheetand/or a backsheet.

In order for the compression line to be useful as a folding line, thecompression may preferably extend into the absorbent core material.Advantageously, the compression line may extend to a depth correspondingto at least 20% of the core depth, preferably at least 50%, mostpreferred at least 75%.

Examples of compression lines that may be used in this context may befound in EP 0 781 537 A1, U.S. Pat. No. 5,795,344, EP 1 332 742 A1, andWO 00/32146.

The absorbent core material of the illustrated embodiment comprises anupper absorbent core 8 and a lower absorbent core 9. The lower absorbentcore will be closer to a garment facing side of the article than theupper absorbent core.

In FIG. 1 the shapes of the upper absorbent core 8 (whole line) and thelower absorbent core 9 (broken line) are illustrated. In this case, theupper absorbent core 8 is hour-glass shaped, whereas the lower absorbentcore 9 is generally oval.

The lower absorbent core 9 is thus wider than the upper absorbent core 8as measured at the middle lobe of the article. In particular, the widestportion of the oval of the lower absorbent core is positioned in linewith the waist of the upper absorbent core 8. Hence, the middle convexlobe 3 of the article will be formed by the lower absorbent core 9, andthe first 2 and second 4 convex lobes are formed by the two widersections of the hour-glass shape of the upper absorbent core 8.

The folding lines 5 will in this case extend along the longitudinalsides of the upper absorbent core 8 so as to follow the shape of thewaist of the hour-glass. Hence, the side portions 7 will compriseabsorbent material from the second absorbent core 8 only.

Further, the upper absorbent core 8 is longer than the lower absorbentcore 9 as measured in the longitudinal direction of the article 1.Hence, the centre region of the central portion 6 of the article willcontain the maximum amount of absorbent material, which is suitablesince this area is the general area of impact of body fluids. The frontand back regions of the article will be somewhat thinner than the centreregion, which contributes to a comfortable product without unnecessarybulk.

The lower absorbent core 9 being wider than the upper absorbent core 8and essentially forming the side portions 7 has the additional advantagethat the product, when in use, will have an increased tendency to formsuch that the side portions 7 extend upwards towards the wearer.

In the illustrated embodiment, the thickness of the article at of theside portions 7 is less than the thickness of the central portion 6 atthe middle lobe 3, since the side portions 7 include absorbent materialof the lower core 9 only, whereas the central portion 6 at the middlelobe 3 includes material from the upper core 8 and the lower core 9.

The thickness of the side portions 7 being less than the thickness ofthe central portion 6 at the middle lobe 3 contributes to the tendencyof the side portions 7 to fold and deform rather than the centralportion 6. The desired difference in thickness may in other embodimentsbe obtained using only one absorbent core, or using more than two cores.

In the exemplified embodiment, the thickness of the central portion 6 isabout 11 mm, and the thickness of the wings is about 7 mm, althoughthese dimensions may of course be varied for different types or sizes ofproduct.

In order to control the deformation of the article 1 when in use, suchthat the side portions 7 will fold and deform rather than the centralportion 6, it has been found that the flexural rigidity of the sideportions 7 in relation to the central portion 6 at the middle lobe 3 isof importance.

In particular, the flexural rigidity as measured in a cross-direction ofthe article at the side portions 7 and of the central portion 6 has beenfound to be relevant in order to provide a product where the deformationtakes place mainly at the side portions 7.

“Flexural rigidity” as used herein refers to measures obtained by theflexural rigidity test which is described later on in this application.

Advantageously, the flexural rigidity of the article 1 at the sideportions 7 is between 3 and 20% of the flexural rigidity of the centralportion (6) at the middle lobe (3) of the article (1), as mentionedabove. The flexural rigidities are measured according to the method asdescribed herein. In the illustrated embodiment, said flexural rigidityis about 8.7% if using maximum load measures.

FIGS. 3 and 4 illustrate schematically a second embodiment of anarticle. The second embodiment differs from the embodiment of FIGS. 1and 2 in that the upper core 8 is wider than the lower core 9. Further,the upper core 8 is shorter than the lower core 9. In the illustratedembodiment, the upper core 8 is generally oval shaped, and the lowercore 9 is generally hour-glass shaped. This embodiment has anaesthetical advantage in that the side portions 7 will start from theupper portion of the product. The folding lines 5, in this case beingcompression lines, are formed in the upper core 8, extending along theperiphery of the lower core 9.

Apart from the different configuration of the cores, the secondembodiment depicted in FIGS. 3 and 4 is similar to the first embodimentdescribed in relation to FIGS. 1 and 2, which is why the features andadvantages as set out above in relation to the first embodimentgenerally apply also to the second embodiment.

In FIGS. 5 and 6, the various components of the article of FIGS. 1 and 2are shown in more detail. (Similar features could be added to theembodiment illustrated in FIGS. 3 and 4.) The absorbent articlecomprises an absorbent core consisting of the upper absorbent core 8 andthe lower absorbent core 9, and a cover enclosing the absorbent core.Said cover comprises a liquid pervious topsheet 103 on the wearer facingside of the absorbent core and a liquid barrier backsheet material 104on the garment facing side of the absorbent core.

The topsheet 103 forms the inner cover of the absorbent article and inuse is placed in direct contact with the skin of the wearer. Thetopsheet can comprise a nonwoven material, e.g. spunbond, meltblown,carded, hydroentangled, wetlaid etc. Suitable nonwoven materials can becomposed of natural fibers, such as woodpulp or cotton fibres, manmadefibres, such as polyester, polyethylene, polypropylene, viscose etc. orfrom a mixture of natural and manmade fibres. Further examples of innerliquid permeable cover materials are porous foams, apertured plasticfilms, laminates between apertured films and nonwovens etc. Thematerials suitable for inner liquid permeable cover materials should besoft and non-irritating to the skin and be readily penetrated by bodyfluid, e.g. urine or menstrual fluid. The inner liquid permeable covermay further be different in different parts of the absorbent article.

The backsheet material 104 may be a thin plastic film, e.g. apolyethylene or polypropylene film, a nonwoven material coated with aliquid impervious material, a hydrophobic nonwoven material, whichresists liquid penetration or a laminate comprising plastic films andnonwoven materials. The backsheet material 104 may be breathable so asto allow vapour to escape from the absorbent core, while stillpreventing liquids from passing therethrough. Examples of breathablebacksheet materials are porous polymeric films, nonwoven laminates fromspunbond and meltblown layers, laminates from porous polymeric films andnonwovens.

The absorbent core material can be of any conventional kind. Examples ofcommonly occurring absorbent materials are cellulosic fluff pulp, tissuelayers, highly absorbent polymers (so called superabsorbents), absorbentfoam materials, absorbent nonwoven materials or the like. It is commonto combine cellulosic fluff pulp with superabsorbent polymers in anabsorbent core. Superabsorbent polymers are water-swellable,water-insoluble organic or inorganic materials capable of absorbing atleast about 20 times their weight in an aqueous solution containing 0.9weight percent of sodium chloride. Organic materials suitable for use asa superabsorbent material can include natural materials such aspolysaccharides, polypeptides and the like, as well as syntheticmaterials such as synthetic hydrogel polymers. Such hydrogel polymersinclude, for example, alkali metal salts of polyacrylic acids,polyacrylamides, polyvinyl alcohol, polyacrylates, polyacrylamides,polyvinyl pyridines, and the like. Other suitable polymers includehydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch,and isobutylene maleic anhydride copolymers and mixtures thereof. Thehydrogel polymers are preferably lightly crosslinked to render thematerial substantially water insoluble. Preferred superabsorbentmaterials are further surface crosslinked so that the outer surface orshell of the superabsorbent particle, fiber, flake, sphere, etc.possesses a higher crosslink density than the inner portion of thesuperabsorbent. The superabsorbent materials may be in any form suitablefor use in absorbent composites including particles, fibers, flakes,spheres, and the like.

A high absorption capacity is provided by the use of high amounts ofsuperabsorbent material. For an absorbent core comprising a matrix ofhydrophilic fibers, such as cellulosic fibers, and superabsorbentmaterial, the proportion of superabsorbent material is preferablybetween 10 and 90% by weight, more preferably between 30 and 70% byweight.

The absorbent core may comprise layers of different material withdifferent properties with respect to liquid receiving capacity, liquiddistribution capacity and storage capacity. The thin absorbent bodies,which are common in for example baby diapers and incontinence pads,often comprise a compressed mixed or layered structure of cellulosicfluff pulp and superabsorbent polymers. The size and absorbent capacityof the absorbent core may be varied to be suited for different uses suchas for infants or for adult incontinent persons.

Other examples of absorption materials useful as absorbent cores arelaminates of roll materials, such as airlaid tissue, nonwovens andthrough-air-dried tissue, and superabsorbent materials, wherein an innerlayer or strings of superabsorbent material is present between outerlayers of said roll material. The different layers are bonded togetherby for example glue or by heat bonding.

In the exemplified prior art product, the absorbent core comprises twolayers, an upper layer 8 and a lower layer 9. In other embodiments onlyone layer or three or more layers may be present. Further, each of the“upper layer” 8 and the “lower layer” 9 may comprise one or morematerial layers.

A liquid transfer layer 105 may be arranged between the topsheet 103 andthe absorbent core material. The transfer layer is a porous, resilient,relatively thick material layer, for example in the form of a fibrouswadding, a carded fibrous web, a tow material or other type of bulky andresilient fibrous material having a high momentaneous liquid receivingcapacity and which can temporarily store liquid before it is absorbed bythe underlying absorbent body. The liquid transfer layer may further bein the form of a porous foam material. It may further consist of two ormore material layers. The basis weight of the transfer layer is between20 and 100 g/m², preferably between 30 and 80 g/m².

The absorbent article may be provided with an adhesive at agarment-facing side thereof, so as to enable fastening of the article tothe undergarment of a wearer. In this case, the garment facing side ofthe article 1 is preferably free from adhesive at the side portions 7,such that the side portions 7 are not restricted in their folding by theundergarment.

Flexural Rigidity Test

The method is intended to measure the flexural rigidity or resistance ofan article when it is folded in a specific fixture. In the context ofthis application, the method is used to describe the characteristics ofthe side portions and the central portion of a product, in order to forman article suitable for adjustment to the shape of the body, when thearticle is placed in an undergarment. The measurement method haspreviously been used for thin products such as sanitary napkins with DryFormed Reel core, panty liners with High Densified Core and panty linerswithout core.

FIG. 7 is a schematic side view of the equipment used for performing theflexural rigidity test. FIG. 8 is another schematic side view of theequipment, as seen perpendicular to the view of FIG. 7.

The equipment comprises a base fixture 201 for supporting an article 1to be measured, and an upper fixture 202 to be lowered down onto thearticle 1 when resting on the base fixture 201.

The base fixture 201 comprises a base means 207 including a holder forattachment to a tensile tester. The base means 207 is provided with twosupport means 203 a and 203 b. Each support means 203 a, 203 b comprisestwo generally vertical bars and a horizontal bar 204 extendinghorizontally between the two generally vertical bars. The support means203 a, 203 b are attached to the base means 207 in a position so as tolean somewhat towards each other. Hence, the distance between the centreof the support means 203 a, 203 b at the base means 207 is about 87 mm,and the distance between the centers of the support means 203 a, 203 bat the horizontal bars 204 a, 204 b is only 40 mm. The horizontal bars204 a, 204 b extend horizontally and in parallel.

The horizontal bars 204 a, 204 b are covered with Teflon® and have acircular cross-section with a diameter of 10 mm (including the Teflon).The surface of the horizontal bars is smooth.

The upper fixture 202 includes a holder 206 for attachment to a tensiletester, and a metal wire structure 205. The metal wire structure 205comprises a horizontal portion for contacting the product 1 when loweredtowards the base fixture. The horizontal portion has a length of 140 mm.At its two ends, the horizontal portion is attached to verticallyextending wire portions, having a length of 50 mm. Thereafter, the wireportions continue with angled wire portions, also having a length of 50mm, and leaning towards each other such that the upper ends of theangled wire portions are separated by a distance of 90 mm. The angledwire portions are each followed by a second horizontal wire portionhaving a length of 50 mm. Finally, the second horizontal wire portionsare attached to a fixture member 206. The distance between the secondhorizontal wire portions at the fixture member 206 is thus 90 mm.

The metal wire has a diameter of 3 mm, and is made of a rigid andinflexible material.

The upper fixture 202 is arranged in relation to the base fixture 201such that the wire structure 205 is perpendicular to the horizontalsupports 204 a, 204 b.

For testing, the fixtures 201, 202 are mounted to the tensile tester.The upper fixture is adjusted such that the distance between thehorizontal metal wire and the uppermost side of the sample when restingon the base 207 of the base fixture is about 2 mm. With this distance,the sample may easily be positioned on the base fixture. The sampleshall be positioned such that the upper fixture will impact the middleof the sample.

For testing, the upper fixture is lowered towards the sample with avelocity of 200 mm/min, so as to push the product down between thehorizontal supports. The test is finished when the entire product hasbeen pushed down between the supports.

If the article to be tested is provided with an adhesive covered by arelease paper, the release paper is removed and the adhesive is powderedwith talc so that no stickiness from the adhesive is maintained beforetesting.

The samples shall be conditioned for at least 4 hours at 23±2° C. and50±5% relative humidity before testing.

For each test, the maximum force obtained is recorded.

The force obtained when testing is defined as the resistance when thesample resting on the Teflon covered base fixture is folded down intothe same by the downwardly moving metal wire of the upper fixture.

Equipment Used:

Tensile tester: e.g. Lloyd LRX

Load cell: 20N

Velocity: 200 mm/min

Thickness Measurement

The thickness of the four products was measured using a conventionalmethod, using a compression pressure of 0.5 kPa.

Results

The flexural rigidity of the side portions and central portions of fourproducts was measured using the method described above.

Before testing, the side portions were cut off from the central portionof each article.

Thereafter, the side portion was placed resting on its longitudinal edgeon the horizontal bars of the test equipment, and the wire structurelowered towards the side portion such that the wire structure isperpendicular to the other longitudinal edge of the side portion.

The flexural rigidity of the central portion was measured with thecentral portion placed flatly on the horizontal bars of the testequipment, with the garment facing side facing downwards. The centralportion was placed such that the wire structure extended along thelength direction of the central portion, “dividing” the central portioninto two longitudinal halves.

The use of the flexural rigidity test as described above in thisparticular manner is believed to be useful to indicate the requirementsof rigidity of the side portions in relation to the rigidity of thecentral portion in order to achieve folding of the side portions ratherthan creasing of the side portions and/or the central portion when theproduct is subject to compression between the thighs of a user. It isunderstood that the values obtained for the side portions and thecentral portion are not immediately comparable. In order to havecomparable values, it might actually be more suitable to measure alsothe side portions longitudinally. However, since such a measurement ispractically inconvenient, it has been replaced by the above-describedmeasurement where the side portion is placed on its longitudinal edgeand transversely compressed. Nevertheless, the selected method isbelieved to provide values being suitable for evaluating the deformationproperties of the product.

The maximum load results appear in Table 1 below.

TABLE 1 Central portion— Side portion— length cross direction Product nodirection (N) on edge (N) 1 7.1 0.43 2 8.8 0.55 3 7.4 0.93 4 9.1 0.56

The average maximum load for the central portions was found to be 8.1 Nwhich may be compared to the average maximum load in the cross directionfor the side portions which was 0.62 N. Hence, in this case the maximumload of the article at the side portions is on average about 7.9% of themaximum load of the article at the central portion as measured herein.On discounting article 3 which shows a slightly different value than theother articles, the values are found to be rather constant about 6.2%.Hence, values between 5.5 and 7% are believed to be particularly useful.

The measurements of maximum load may be sensitive to irregularities inthe product and to errors in the test procedure. For example,insufficient provision of talc to an adhesive on the garment facing sideof the product might lead to erroneous values, as may creases on thegarment facing side of the product.

For testing wider products than the ones described above, longerhorizontal bars as well as a longer horizontal wire portion may be used.

Four corresponding products were used for measuring the thickness of theside portions and of the central portion. In this case, the thickness ofboth of the side portions of each article was measured.

The thickness of the central portion was measured at the centre of thecentral portion itself, i.e. at the centre of the middle lobe of theentire article. The thickness of the side portions was measured at thecentre of each side portion. The thickness measurements shall beperformed before cutting the products in pieces for the flexuralrigidity test.

The results of the thickness measurements appear in Table 2 below:

TABLE 2 Central 1^(st) Side 2^(nd) Side Product no portion (mm) portion(mm) portion (mm) 1 12.0 6.6 6.7 2 12.1 8.1 7.1 3 11.3 6.7 6.1 4 10.46.4 6.3

The average thickness for the central portions was found to be 11.45 mmwhich may be compared to the average thickness for the side portionswhich was 6.75 mm. Hence, in this case the thickness of the article atthe side portions is about 59% of the thickness of the article at thecentral portion as measured in the cross direction.

Hence, the thickness of the side portions of the measured articlesamounts to about 59% of the thickness of the central portions and theflexural rigidity of the side portions is about 7.9% of the flexuralrigidity of the central portions (if expressed in maximum load).

It will be understood that several embodiments and variants of thedisclosed embodiments are possible. The shape of the absorbent core maybe varied, as may the individual shapes of the upper and lower core whentwo cores are used. The side portions could include material from twocores, and the lengths of the two cores may be varied. The compressionlines could be restricted to an upper core and to a surface material,through one core only, or through two cores. Further, additional coresmay be used. The materials of different layers of the product may bevaried, as may the thickness and layout of different layers.

Further, although the described embodiment is a three-lobe shapedproduct, it is understood that the idea is applicable to products beingdifferently shaped. References being made in the description to thethickness or flexural rigidity of the central portion at the middle lobeare understood to be equivalent with the thickness or flexural rigidityof the central portion at a location opposite the side portions, inembodiments where there is no “middle” lobe present.

Further, it is understood that the function of several of the featuresdescribed in relation to the present disclosure, although providing anhighly advantageous result when provided in combination, may be usedseparately in order to achieve the advantages described in relation toeach feature.

1. An absorbent article having a length and a width extension, saidlength being greater than said width, comprising: absorbent corematerial, the absorbent core material forming a central portion and apair of longitudinal side portions, wherein a pair of folding lines isprovided so as to divide said absorbent core material into said centralportion and said pair of longitudinal side portions and a flexuralrigidity of the article at the side portions is between 3 and 20% of aflexural rigidity of the article of the central portion at a locationopposite the side portions, and wherein each of the pair of longitudinalside portions is located at a respective end of the width extension. 2.The absorbent article according to claim 1, wherein the flexuralrigidity of the article at the side portions is between 0.35 and 1.1. 3.The absorbent article according to claim 1, wherein the flexuralrigidity of the article at the central portion at a location oppositethe side portions is between 6.5 and 10.1.
 4. The absorbent articleaccording to claim 1, wherein a thickness of the article at the sideportions is less than a thickness of the central portion at a locationopposite the side portions.
 5. The absorbent article according to claim4, wherein the thickness of the article at the side portions is between40 and 80% of the thickness of the article at a location opposite theside portions.
 6. The absorbent article according to claim 1, whereinthe folding lines are formed by compression of the absorbent material.7. The absorbent article according to claim 1, wherein the folding linescompletely separate the absorbent material in the side portions from theabsorbent material in the central portion.
 8. The absorbent articleaccording to claim 1, wherein the folding lines only partly separate theabsorbent material in the side portions from the absorbent material inthe central portion.
 9. The absorbent article according to claim 1,wherein the folding lines are positioned and extending along a lengthsuch that, when the article is in use, the folding lines are generallypositioned so as to extend along the crotch area of a user, startingfrom the gracilis tendons and ending in the region of the perineum,whereby the side portions may extend from the central portion towardsthe user so as to form an arc shape as seen in a transversal directionof the article.
 10. The absorbent article according to claim 1, whereinthe folding lines have a length of about 60 to 170 mm.
 11. The absorbentarticle according to claim 1, wherein the folding lines extend alongabout ⅓ of the total length of the article.
 12. The absorbent articleaccording to claim 1, wherein outer longitudinal edges of said absorbentmaterial form three convex lobes, said pair of folding lines extendconcavely between the longitudinal ends of a middle one of said threelobes, so as to divide the absorbent core material into said centralportion and said pair of longitudinal side portions, such that, when thearticle is in use, the folding lines are generally positioned so as toextend along the crotch area of a user, starting from the gracilistendons and ending in the region of the perineum, whereby the sideportions may extend from the central portion towards the user so as toform an arc shape as seen in a transversal direction of the article. 13.The absorbent article according to claim 12, wherein the length betweenthe longitudinal ends of the middle lobe is about 60 to 270 mm.
 14. Theabsorbent article according to claim 12, wherein the middle lobe extendsalong about ⅓ of the total length of the article.
 15. The absorbentarticle according to claim 14, wherein each lobe extends along about ⅓of the total length of the article.
 16. The absorbent article accordingto claim 12, wherein a maximum width of the middle lobe is between60-150 mm.
 17. The absorbent article according to claim 12, wherein amaximum width of the middle lobe divided by a width of one of the endsof said middle lobe is between 110 and
 180. 18. The absorbent articleaccording to claim 12, wherein a distance between a maximum width of themiddle lobe and an adjacent said folding line is less than 30 mm. 19.The absorbent article according to claim 12, wherein a minimum width ofthe article is the width as measured at either of the ends of the middlelobe.
 20. The absorbent article according to claim 12, wherein thewidths at the two ends of the middle lobe are essentially the same. 21.The absorbent article according to claim 12, wherein the widths at theends of the middle lobe are in the range 30 to 100 mm.
 22. The absorbentarticle according to claim 12, wherein three points positioned on thelongitudinal side of the article at the location of a widest portion ofeach of the three lobes are positioned along a straight line.
 23. Theabsorbent article according to claim 12, wherein maximum widths of thethree lobes are substantially the same.
 24. The absorbent articleaccording to claim 1, wherein a garment facing side of the article isfree from adhesive at the side portions.
 25. The absorbent articleaccording to claim 1, wherein the absorbent core material comprises anupper absorbent core and a lower absorbent core.
 26. The absorbentarticle according to claim 25, wherein one of the upper and lowerabsorbent cores is wider than the other of said upper and lowerabsorbent cores as measured at the side portions of the article.
 27. Theabsorbent article according to claim 26, wherein the folding linesextend along the longitudinal sides of the least wide of the upper andlower absorbent cores, such that said side portions essentially compriseabsorbent material from one of the absorbent cores only.
 28. Theabsorbent article according to claim 27, wherein a thickness of thearticle at said side portions includes the thickness of only one of thelower absorbent core and the upper absorbent core, and a thickness ofthe article at the central portion opposite the side portions includesthe thickness of the lower absorbent core plus the thickness of theupper absorbent core.
 29. The absorbent article according to claim 25,wherein one of the upper and lower absorbent cores is longer than theother one of said upper and lower absorbent cores as measured in thelongitudinal direction of the article.
 30. The absorbent articleaccording to claim 25, wherein the least wide of the cores as measuredat the side portions is generally hour-glass shaped.
 31. The absorbentarticle according to claim 25, wherein the widest one of the cores asmeasured at the side portions is generally circular or oval.
 32. Anabsorbent article having a length and a width extension, said lengthbeing greater than said width, comprising: absorbent core material, theabsorbent core material forming a central portion and a pair oflongitudinal side portions, wherein a pair of folding lines is providedso as to divide said absorbent core material into said central portionand said pair of longitudinal side portions, and wherein a thickness ofthe article at the side portions is between 40 and 80% of the thicknessof the article at a location opposite the side portions, and whereineach of the pair of longitudinal side portions is located at arespective end of the width extension.
 33. An absorbent article having alength and a width extension, said length being greater than said width,comprising: absorbent core material, the absorbent core materialcomprising an upper and a lower absorbent core, wherein one of the upperand lower absorbent cores is wider than the other of said upper andlower absorbent cores as measured at side portions of the article,wherein folding lines extend along the longitudinal sides of the leastwide of the upper and lower absorbent cores, such that said sideportions comprise absorbent material from one of the absorbent coresonly, and wherein each of the side portions is located at a respectiveend of the width extension.